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One thing to be careful of if you sub a green or amber CRT into a Mac is the longer persistence phosphors in them are somewhat more prone to burn-in than the white TV phosphor the Mac came with. Probably not a big deal considering how much use a toaster Mac is likely to get in the real world...

I didn't see this answered earlier, I apologize if I'm blind. Asterisks like that usually mean "active low". (IE, the line is pulled to zero to activate the named function. This is usually the case for chip selects. Not universally so, but usually, because TTL process chips in particular tend to...

So, yeah, there you go, HD media is the correct choice. The Twiggy just sort of sucks at using it. ;)

HD disks are utterly hopeless in drives like the C1541 (and Disk II/TRS-80 Whatever/IBM 5150/etc), the magnetic coating on them is far too stubborn for the pipsqueaky powers of a double-density head. On the other hand, my recollection is that according to "those who know" the magnetic coercivity...

I had one of those Radio Shack Science Fair 150-in-1 things with the springs when I was a kid, that's probably my most relevant qualification.

That's the important part. Isn't the GAL's fault that this board has that ridonkulous number of RAM chips. If you had fewer larger ones it'd do the job all by itself.

Yay! GALs are truly magical.

There's a number of weird things about PCBWay's pricing model. Their 10 for $5 is a helluva deal as long as your prototype is under 100mm in any dimension, but the pricing takes a huge leap if you exceed that. My most recent project was 100x150 mm and five boards from PCBway at that size gets...

The original code I wrote only enables OE and WE based on the opposite state of the RW output lines from the bus: There shouldn't be any circumstance under which it would enable both at once unless there's some internal delay in play here since RAMOE is dependent on the feedback from MEMCS...

I think I'll get away with having my bodge on the bottom where no one can see it. There's a via I can drill out to make the fix routeable on the dark side. ;) When you get things so you can actually plug it in I guess we'll find out if /DELAYCS is actually a needed part of the equation. I do...

So I guess we're even on forgetting to add traces. I was testing the last untried section of my uberboard last night, the EMS page flipper, and found it was completely fouled up. (It looked like pages were being shuffled around essentially at random. I was able to confirm this was what was...

I couldn't get CUPL to run on Windows 10 at all without crashing. Futzed around for hours trying to install ancient runtime packages and nothing helped. Last week because I'm apparently a stupid glutton for punishment I actually did get it working on WINE, it seems to work fine on that. I...

Ooof. Yeah, if it was just connected to a different pin you'd be fine, but you do need it to be there somewhere. :)

... manual routing in Kicad works pretty well, actually, as long as you enable the option that gives you "springy" traces and automatic stitching of segments. For some bizarre reason that was disabled when I installed it. I have *no idea* who thought that was a sensible default.

I actually looked into it after you mentioned it, and my eyes totally glazed over between it needing that manual export stage and it requiring a Java runtime to execute. ;)

For us mere mortals there's Kicad. It's... totally okay, really! (When I first started using it I really wished it had a functioning autorouter but, hey, routing by hand is an interesting puzzle challenge.)

I actually had to file the pins down on a right-angle ISA slot connector I bought once to fit it into a board that had too-small holes once and that was *not* fun, and in that case the size mismatch was a lot less so, yeah, it'd be really hard. Only chance would be a motorized sanding wheel and...

Is there any possibility of shortening the pins on that connector? I can't clearly see how they're constructed, are the uprights thicker metal with the smaller solderable pin set inside the end, or is there an insulator around a contact that's all around the upright pin that at least in theory...

Isn't it amazing how things never *just clear* the possible obstruction by a quarter millimeter, it's always the reverse? I'd suggest you could try at least testing things by sticking a stacking header between the board and the motherboard to raise it up enough to clear the PDS slot, but then...

For whatever it's worth I just started testing my first GAL-powered board (the one I dropped a picture of earlier) and so far things are working. The memory decoder GAL so far/knock on wood seems to have been 100% correct first try, I've had to make a couple corrections to the I/O decode GAL...